I agree with the need for a more interesting palette, but I think the thing that needs the most work is the shading. The dragon itself is nice and I also like the texture, but the way you've shaded it makes it look flat. I don't think the angles of the upper and lower jaws look right. The lower jaw seems a bit twisted out of shape since we're not seeing it more from the side like the upper jaw. It also looks like he's missing his front teeth where the tongue lies, so I think it would be a good idea to lift it a bit right where the teeth should be.

Here's an edit showing the things I mentioned. Hope that's helpful, and good luck with the voting.